1. Field
Embodiments disclosed herein generally relate to a magnetic disk device employing a microwave assisted magnetic recording head.
2. Description of the Related Art
Over the past few years, microwave assisted magnetic recording (MAMR) has been studied as a recording method to improve the areal density of a magnetic read/write device, such as a hard disk drive (HDD). MAMR enabled magnetic recording heads utilize a spin torque oscillator (STO) for generating a microwave (high frequency AC magnetic field). When the magnetic field from the write head is applied and current is conducted to the STO, the STO oscillates and may provide an AC magnetic field to the medium. The AC magnetic field may reduce the coercive force of the recording medium, thus high quality recording by MAMR may be achieved. Typically the STO includes a reference layer, a field generation layer (FGL) and an interlayer disposed between the reference layer and the FGL. The interlayer may be a non-magnetic layer having low electrical resistance, thus, the current flowing to the STO also flows in the in-plane direction within the interlayer.
The STO may be fabricated by laminating integrally with the MAMR head, and may be formed near the trailing side of a main pole. To increase the recording magnetic field, a tapered write pole (TWP) type main pole with a trailing edge taper (TET) configuration may be utilized and the STO may be formed near TET configuration in a TWP type main pole. In this configuration, the STO may not be perpendicular to a media facing surface (MFS), such as an air bearing surface (ABS). Because the current flowing to the STO tends to be parallel to the ABS, the current flowing to the STO is not perpendicular to the STO, which causes the spin torque to decrease. Therefore, an improved STO structure is needed.